In general, a refrigerator is an apparatus for storing various types of items, e.g., food, at low temperature. Low temperature in the refrigerator is achieved by circulating cold air that can be continuously generated through a heat exchange process by using a refrigerant. During operation, the refrigerant goes through repetitive cycles of compression, condensation, expansion and evaporation.
A main body of the refrigerator may have a rectangular parallel-piped shape with an open front surface. Typically, the main body encloses a refrigeration room or compartment and a freezer compartment, each with its own door. The refrigerator may include a plurality of drawers, shelves, vegetable compartments and the like for sorting and storing different types of items.
Conventionally, top mount type refrigerators were widely used, with a freezer compartment positioned at the upper side and a refrigeration compartment positioned at a lower side. Recently, the bottom freezer type refrigerators have been developed, where a freezer compartment is located at the lower side and a refrigeration compartment is located at the top. Because typically users access the refrigeration compartment more often than the freezer compartment, a bottom freezer type refrigerator allows a user to conveniently access the refrigeration compartment that is located at the upper portion of the refrigerator. Unfortunately, on the other hand, it can be inconvenient for a user to access the freezer compartment if the user often needs to lower or bend down to access the freezer compartment, e.g., for taking ice out of the freezer compartment.
Therefore, some bottom-freezer-type refrigerators are equipped with a dispenser for dispensing ice, e.g., ice cubes or crushed ice. The dispenser is typically located in a refrigeration compartment door. Accordingly, the ice-making device for producing ice may be installed in the refrigeration compartment door or the interior of the refrigeration compartment.
In a bottom-freezer-type refrigerator with an ice-making device installed in a refrigeration compartment door, a cold air flow produced by an evaporator can be supplied into the freezer compartment and the refrigeration compartment. In the freezer compartment, cold air flows toward the ice-making device along a cold air supply duct embedded in a sidewall of a refrigerator main body. Thus, the cold air freezes water into ice pieces while flowing through the interior of the ice-making device. The cold air is then discharged into the refrigeration compartment via a cold air return duct embedded in the sidewall of the refrigerator main body, thereby lowering the temperature in the refrigeration compartment.
However, in a conventional refrigerator, the cold air supply duct, the cold air return duct and a structure for insulating the ducts need to be mounted on the left or right wall surface portion of the refrigeration compartment. Unfortunately, these components occupy a lot of space and reduce the storage capacity of the refrigerator. They also tend to complicate the pipe arrangement inside the refrigerator.
Furthermore, ice pieces in the refrigerator door are produced by an indirect cooling process in which cold air flows through the cold air supply duct. Thus, water in the refrigerator door cannot be directly cooled by a refrigerant, and the ice-making rate is low.